What is polymer concrete?
A characteristic difference of such a concrete mixture is the addition of high molecular weight organic compounds in the manufacture. In fact, polymer concrete is a mixture where various polyester and other resins can perform the role of a binder: polyurethane, polyvinyl, epoxy, methyl methacrylate and others, in combination with hardeners, catalysts, solvents, and so on.
Geopolymer concrete, the composition of which differs from mixtures based on Portland cement, is used for external and internal decoration of buildings and premises, landscape and repair work, while creating small architectural forms. It can be used on both horizontal and vertical surfaces, depending on the technology used and its consistency.
Characteristics of geopolymer concrete
Such material consists of a mixture of slag, ash, liquid glass, as well as other components added in the right proportion. The polymerization taking place in this mixture forms a monolith, which in physical and chemical properties and technical characteristics exceeds the ordinary concrete.
Geopolymer concrete, also polymer or composite, has a number of advantages over portland cement mixtures, namely:
- very high adhesion to any surface;
- short term hardening;
- high permeability;
- high degree of resistance to bending and stretching;
- increased strength and durability;
- resistance to temperature changes and acidic effects.
In addition, this environmentally friendly material has a low specific gravity. Probably, the only drawback that prevents widespread use of this type of concrete is its high cost. But scientists believe that the future of the construction industry is behind this material.
Geopolymer concrete can be made by hand only in an experimental way. Since the material is in the development stage, the exact formulation is not available in the public domain.
Features of the preparation of polymer concrete
The most frequently used as additives are PVA, water-soluble resins and various latexes. PVA is used in a special consistency, where polyvinyl alcohol acts as an emulsifier.
When the mixture dries, a solid film crystallizes on the surface, which swells, absorbing water, so the regime of high humidity is not recommended for the production of such concretes. At repeated drying the strength of polymer concrete becomes the same.
The optimum amount of additives to be added should be experimentally established. The key to successfully obtaining a quality concrete mix is the correct ratio of polymers and cement. The optimum amount of additive added is about 20% of the total weight of the cement.
Water-soluble resins are introduced into concrete in small doses - about 2% of the total mass of the cement. The most qualitative mixture is obtained by the addition of water-soluble epoxy and polyamide resins in combination with a polyethylene-polyamine hardener.
Geopolymer concrete mixtures are prepared by analogy with conventional, cement mixtures. To do this, you need a concrete mixer. First, water is added to it with some cement, specially designed for polymer concrete.
Portland cement can not be used here, since it has other properties and characteristics. So to the cement, slag and ash fill up in equal parts. All is thoroughly mixed, then the polymers are added, and the whole composition is further stirred until ready.